Rubber elastic compositions containing aziridine compounds are know for a long time. Curing of these compositions is usually effected using specific catalysts.
In this respect U.S. Pat. No. 4,167,618 A1 describes a process for the polymerization of aziridine compounds. The polymerization process includes mixing an aziridine compound with an alkyl sulfonium salt initiator having at least one hydrogen atom and an electron attracting radical in the carbon atom of the alkyl group in β-position in regard to the sulphur atom.
WO 01/17483 A1 relates to elastomer materials based on N-alkyl aziridine compounds comprising a base constituent, which contains aziridine compounds, and comprising a catalyst constituent, which contains at least one acidically active compound, whereby both constituents are mixed before use. The elastomer materials are characterized in that one or more boric acid complexes are used as an acidically active compound of the catalyst constituent. The elastomer materials can be used as dental impression material, bite recording material, and duplicating material.
In DE 19 753 456 A1 a two-component cationically-curable aziridine polyether-based composition is described, comprising a catalyst component, including acid(s) and aziridine salt(s) of an acid, and a base component including a mixture of N-alkylaziridine polyol ethers and a cationic polymerization retarding agent(s).
US 2003/153726 A1 relates to catalyst components containing at least one Brönsted acid, water and at least one antacid-acting compound. The catalyst components can be used to initiate cure of an aziridino-group-containing material.
Depending on the intended use, in the dental field the materials usually have different viscosities (light body, medium body, heavy body). In view of the fact that sometimes relatively large amounts of conventional alkyl sulfonium salt initiators are needed to cure aziridine polyether-based compositions, the viscosity of the components of the composition may need to be adjusted to ensure adequate mixing and application of the mixed paste.